The invention pertains to a leak sealing-pad for sealing off the damaged walls of containers and pipes. The leak sealing-pad is rectangular in shape and is manufactured in a press using vulcanized rubber, which prior to vulcanization is not reinforced, but which in the process is reinforced and vulcanized by heat. It has a surface which is applied to the leak and an opposing surface which is equally as large and which faces away from the leak. These two surfaces are joined at their edges and thus describe an air-tight inner chamber which can be accessed from outside via a nipple. In addition, there are mounted on two opposite edges hooks, eyes, loops and the like for a device which spans the container or, as the case may be, the pipe.
With the aid of such leak sealing-devices, damaged containers or piping can be sealed off simply and with a minimum of exertion. The devices are of particular value when it is necessary to seal off a leaking section that has been damaged in an accident or the like, the purpose being to stop as quickly as possible the discharge of dangerous substances from containers or pipes in order to keep as minimal as possible resulting damage, especially pollution of the environment or the danger of an explosion.
In a device that is familiar from the U.S. Pat. No. 4,202,379 and can be employed for sealing off damaged walls of the type described above, an inflatable pad is employed. The pad is made from two vulcanized, reinforced rubber or caoutchouc surfaces which are attached to a side of a flexible counter-plate. This device has, like the pad, rectangular shape, although it is larger than the inflatable pad. Inserted in the mutually opposite narrow sides, are metal rods by means of which the attachments are formed. A valve is incorporated as a nipple in the middle of the surface which faces away from the leak. This valve projects through an opening of the counter-plate and is accessible from the outside.
The flexible counter-plate is reinforced by longitudinal reinforcing threads or elements, which run at right-angles to the metal rods and are placed around the metal rods. Compared to a rigid counter plate of the kind familiar from the text of German Registered Utility Model No. DE-GM 19 20 243 concerning sealing devices, the flexible counter-plate has the advantage that it can be accommodated to a quite considerable extent to the curvature of the damaged container or pipe. Thus the pad is pressed uniformly along its entire surface against the damaged section, and the leak-sealing device can be used almost universally and without being limited to special diameters or forms of containers or pipes. For all practical purposes the counter-plate will not expand in the direction of the reinforcing, and it ensures that the pad which is sited under it is pressed evenly and along its entire surface against the wall which is to be sealed. At the same time, it prevents a localized and unreasonable expansion of the pad. The volume which the pad must occupy remains relatively small. This in its turn avoids the danger that the damaged wall will be pressed in (or deformed, that is further damaged) in the vicinity of the leak.
One of the disadvantages of the leak-sealing devices already on the market is the rather complicated manufacture of the actual sealing arrangement using a counter plate and an inflatable pad. Reinforcing the counter plate in just one direction, namely the direction of pull of the tension devices, has its disadvantages, because the counter plate by reason of the absence of reinforcing can be more easily stretched in the direction at right-angles to the reinforcing. This results in unevenness in its stretching properties. To manufacture the leak sealing-device out of two separate component parts is also a tedious matter. In addition, such a method of manufacture also increases the weight.
Taking as its starting point the leak sealing-devices which are already on the market and which are described in the opening section of this paper, it was the purpose of the invention to avoid the disadvantages of this type of leak-sealing pad and to develop and improve the sealing-device by (1) having the counter plate and the pad constitute one piece right from the initial stage of manufacture, (2) having the pad-surface that is placed against the leak as flexible as possible even after reinforcing so that it can assume a convex shape when inflated, while (3) the pad-surface which faces away from the leak is deformed as little as possible in spite of its reinforcing and its flexibility.